Tubing Pressure Actuated Safety Valve

ABSTRACT

A tubular isolation system is operably connected with a movable member that selectively enables or disables the isolation system at least one time. In an embodiment the movable member is actuated by flow or pressure against a spring bias with an indexing system to regulate movable member movement so that that two opposed positions are attainable. The movable member can be a sleeve with a flow passage therethrough. One way to shift the sleeve is to land a ball on a seat on top of the sleeve and apply a cycle of pressure against the bias so that a j-slot moves the sleeve between end positions. The safety device is dual flappers in one embodiment. The sleeve can also be moved with circulation flow through the tubing with returns coming up the annulus. Alternatively a restriction can be used that later disappears for production.

FIELD OF THE INVENTION

The field of the invention is safety valves for borehole use and more particularly safety valves that can be reconfigured with a tubing pressure cycle.

BACKGROUND OF THE INVENTION

Fracturing a formation frequently involves milling out a series of plugs used to isolate parts of the formation as other parts are fractured with high pressure fluid flow. After all the formation intervals are treated the plug need to be milled out and the production can then begin after the production string is put in place. Typically, a mill and fluid motor are supported by a production string. A work string supports the production string. When the milling is done the production string is hung off. Typically the mill and motor for the mill are allowed to drop in the hole. Doing so leaves the well exposed to a blowout so a safety valve assembly is located in the production string. One form of such blowout protection can be a housing with dual flappers that prevent flow in an uphole direction for the needed blowout protection after the mill and motor are dropped in the hole. The housing with the flappers presents no impediment to running in as the flappers are oriented to open when there is tubing circulation. However, the flappers, if left in place, would prevent production. The technique used in the past is to reverse circulate after dropping the mill. The reverse circulation closes the flappers and releases a housing for the flappers from the string so that the reverse circulation flow can hopefully bring out the flapper assembly. One problem with this design is that the assembly can get hung up on the way out through the tubing or it may just not release from the tubing in the first place. If either of those events occur the need arises for an expensive fishing or milling job to remove the flapper assembly from the production string.

A better way that is addressed by the present invention is to leave the flappers in the string but to isolate them in the open position for production. At the same time there is a need to keep the design simple so it can reliably operate. A sleeve that is normally open is used to open the flappers and advance to the point of holding the flappers out of the way with the option to engage as seal below the flappers to isolate them from well fluids when they are held open. The sleeve is operably connected to a multi-position j-slot or other indexing device so that movement up and down can be accomplished any number of times. The sleeve can be spring biased with movement against the bias actuated with pressure or flow. An upper seal isolates the biasing member from an upper zone where pressure or flow is applied. The uncertainties of the past method of flowing out the flapper assembly is eliminated. The device can have other applications where isolation valves are needed at different times to block or to allow flow with respect to a surface location. These and other aspects of the present invention will be more readily understood by those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims.

SUMMARY OF THE INVENTION

A tubular isolation system is operably connected with a movable member that selectively enables or disables the isolation system at least one time. In an embodiment the movable member is actuated by flow or pressure against a spring bias with an indexing system to regulate movable member movement so that that two opposed positions are attainable. The movable member can be a sleeve with a flow passage therethrough. One way to shift the sleeve is to land a ball on a seat on top of the sleeve and apply a cycle of pressure against the bias so that a j-slot moves the sleeve between end positions. The safety device is dual flappers in one embodiment. The sleeve can also be moved with circulation flow through the tubing with returns coming up the annulus. Alternatively a restriction can be used that later disappears for production.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the run in and operating position for the sleeve that enables the flappers to normally operate;

FIG. 2 is the shifted position of the sleeves that holds the flappers open;

FIG. 3 is a rolled flat view of the j-slot showing the long and short slots corresponding to the sleeve positions in FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As seen in FIG. 1, in one application of the invention, a mill 10 is driven by a fluid motor 12 when attached to the housing 14. Both the mill 10 and the motor 12 can be selectively released after plugs that are not shown that were used in fracturing or otherwise treating a zone are all milled out. Connection 16 is used to connect a production string that is not shown. When the production string is properly supported in a borehole and the FIG. 2 position is assumed production is possible through passage 18 of sleeve 20. Sleeve 20 is biased preferably with a coiled spring 22 but equivalents such as a Belleville washer stack or a chamber with a compressible fluid could be used. Sleeve 20 has an upper seal 24 and a lower seal 26 on opposed sides of the spring 22. A lug or pin 28 rides in a j-slot 30 shown rolled flat in FIG. 3. The FIG. 1 position is attained with the lug in the 28′ position of FIG. 3. The FIG. 2 position is attained with the lug in the 28″ position in FIG. 3. One way the sleeve 20 can be shifted is to land a ball 32 on a seat 34 to block passage 18. Thereafter application and removal of pressure on seated ball 32 will compress the spring 22 and release it as the lug moves from the 28′ to the 28″ positions. When that happens the downward movement of sleeve 20 into the FIG. 2 position pushes dual flappers or closure members 36 and 38 to the fully open position as seal 36 advances into contact with surface 40. The flappers 36 and 38 are now isolated from well fluids between seals 24 and 26. When the well is produced the ball 32 comes off the seat 34 and is produced out of the hole. By this time surface wellhead equipment is in position.

The sleeve 20 can be returned to the FIG. 1 position with another landed ball and a pressure cycle applied.

The movement of the sleeve 20 can also trigger a valve operator such as for one or move formation isolation valves to selectively move between an open and a closed position with the sleeve 20 tied to an actuator. Alternatively the sleeve 20 can be actuated with circulation flow through passage 18 with return flow coming up the annulus since at this time the mill 10 and the motor 12 have already been released after the milling has been completed.

Those skilled in the art will appreciate that when the mill 10 and the motor 12 are released that there needs to be blowout protection for the well and that in one form the dual flappers 36 and 38 serve as the barrier. As previously mentioned, the barrier can take other forms such as formation isolation valves. In the FIG. 1 position the barriers are active to prevent a blowout. However, after the surface safety equipment is in position for production it is advantageous to have passage 18 open for production. In the FIG. 1 position, production would be prevented by the flappers 36 and 38. For production, the flappers 36 and 38 are pushed out of the way behind sleeve 20 and isolated from well fluids by seals 24 and 26. Seal 24 with shoulder 42 act as a piston that responds to application and removal of pressure from above. Another option is to put a restriction in passage 18 that can later be removed by dissolving or disintegrating to allow the use of lower flow rates through passage 18 to move the sleeve 20. This option would have a disadvantage of requiring greater pumping horsepower during fracturing or treating when the flow needs to go through passage 18.

Those skilled in the art will appreciate that the present invention provides for a functioning safety system in a variety of applications where the system can be defeated without need for removal when other safety equipment is installed at the surface. The system can be selectively re-enabled if needed. There is no need for control lines since the sleeve is simply operated with pressure cycles on a seated ball that can be recovered or through flow through the passage in the sleeve.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: 

We claim:
 1. A borehole safety assembly, comprising: at least one closure member to selectively close a passage in a tubular string in the borehole; a movable member actuated with pressure or flow in said passage to selectively disable said closure member from closing said passage with a first movement from a first position to a second position and to subsequently enable said closure member to close said passage with a second movement from a second position back toward said first position.
 2. The assembly of claim 1, wherein: said movable member comprises a sleeve having a passage therethrough.
 3. The assembly of claim 2, wherein: said passage is selectively blocked with an object to move said sleeve with pressure on said object.
 4. The assembly of claim 3, wherein: said sleeve is operably connected to an indexing feature responsive to application and removal of pressure on said object.
 5. The assembly of claim 4, wherein: said sleeve is biased against applied pressure on said object.
 6. The assembly of claim 4, wherein: said indexing feature selectively retains said sleeve in a first and a second position.
 7. The assembly of claim 6, wherein: said sleeve spaced apart from said closure member in said first position.
 8. The assembly of claim 7, wherein: said closure member comprises at least one flapper and said sleeve engaging and moving past said at least one flapper in said second position.
 9. The assembly of claim 8, wherein: said sleeve comprising spaced seals that isolate said at least one flapper from well fluids in said second position with said at least one flapper located between said sleeve and a surrounding mandrel.
 10. The assembly of claim 1, wherein: said closure member comprises at least one flapper and said movable member comprising a sleeve; said sleeve spaced from said flapper in a first position and engaging and moving past said at least one flapper in a second position; said sleeve comprising spaced seals that isolate said at least one flapper from well fluids in said second position with said at least one flapper located between said sleeve and a surrounding mandrel.
 11. The assembly of claim 9, wherein: said sleeve selectively movable from said first to said second and back to said first position using said indexing feature.
 12. The assembly of claim 10, wherein: said sleeve selectively movable from said first to said second and back to said first position.
 13. A borehole safety assembly, comprising: at least one flapper to selectively close a passage in a mandrel; a selectively movable sleeve responsive to flow or pressure in said passage to remain spaced apart from said flapper in a first position and to hold said at least one flapper in an open position in a second position of said sleeve.
 14. The assembly of claim 13, wherein: said sleeve comprising a passage that is selectively blocked with an object to move said sleeve with pressure on said object.
 15. The assembly of claim 14, wherein: said sleeve is operably connected to an indexing feature responsive to application and removal of pressure on said object.
 16. The assembly of claim 15, wherein: said sleeve is biased against applied pressure on said object.
 17. The assembly of claim 15, wherein: said indexing feature selectively retains said sleeve in a first and a second position.
 18. The assembly of claim 15, wherein: said sleeve comprising spaced seals that isolate said at least one flapper from well fluids in said second position with said at least one flapper located between said sleeve and said mandrel.
 19. The assembly of claim 13, wherein: said sleeve comprising spaced seals that isolate said at least one flapper from well fluids in said second position with said at least one flapper located between said sleeve and said mandrel.
 20. The assembly of claim 13, wherein: said at least one flapper comprises multiple flappers oriented to prevent flow uphole to a surface location when said sleeve is in said first position.
 21. A borehole completion method, comprising: milling out at least one plug with a mill attached to a tubular string; providing at least one closure mounted in said string; releasing said mill from the string; relying on said at least one closure as a safety device for the string after releasing the mill; supporting the string in the borehole for use in production; retaining said at least one closure in an open position with applied flow or pressure in the string to permit fluid movement between a surface location and a formation.
 22. The method of claim 21, comprising: defeating said closure with a sleeve having a passage therethrough; moving said sleeve with pressure on an object landed on a seat on said sleeve.
 23. The method of claim 22, comprising: indexing said sleeve between two positions where said closure is enabled and disabled with applied pressure cycles.
 24. The method of claim 23, comprising: using at least one flapper for said closure; providing spaced seals on said sleeve; maintaining said at least one flapper between said sleeve and said tubular string between said spaced seals to isolate said at least one flapper from fluids in the string. 